EP 0141422 B1 19890201 - FREQUENCY DETECTOR
Title (en)
FREQUENCY DETECTOR
Publication
Application
Priority
JP 20931383 A 19831108
Abstract (en)
[origin: US4752742A] A frequency demodulator for a frequency shift keyed (FSK) signal which is modulated by two-level digital signals. The demodulator includes a logic circuit and a quadrature detector having a local oscillator frequency which is substantially equal to the center frequency of the received signal to produce a baseband signal in a quadrature phase relationship. The two-level digital signal is recovered as an output of the logic circuits depending upon whether the received FSK signal frequency is higher or lower than the local oscillator frequency. The demodulator solves the problems centered about a need for analog circuits which are undesirable, from an integrated circuit implementation standpoint. The demodulator avoids spike noise which deteriorates the error rate performance which is commonly found in the prior art (e.g. U.S. Pat. No. 4,521,892).
IPC 1-7
IPC 8 full level
H04L 27/156 (2006.01); G06F 17/22 (2006.01); H04L 27/14 (2006.01); H04L 27/152 (2006.01)
CPC (source: EP KR US)
H03L 7/00 (2013.01 - KR); H04L 27/1525 (2013.01 - EP US)
Designated contracting state (EPC)
DE FR GB NL SE
DOCDB simple family (publication)
US 4752742 A 19880621; AU 3516384 A 19850516; AU 575874 B2 19880811; CA 1232035 A 19880126; DE 3476621 D1 19890309; EP 0141422 A2 19850515; EP 0141422 A3 19860226; EP 0141422 B1 19890201; HK 19091 A 19910322; JP H0129469 B2 19890612; JP S60100859 A 19850604; KR 850003644 A 19850620; KR 900008412 B1 19901120; SG 8491 G 19910405
DOCDB simple family (application)
US 6563987 A 19870626; AU 3516384 A 19841107; CA 467191 A 19841107; DE 3476621 T 19841107; EP 84113417 A 19841107; HK 19091 A 19910314; JP 20931383 A 19831108; KR 840006993 A 19841108; SG 8491 A 19910218